Aircraft performance evaluation model construction and evaluation method based on arm angle influence

Abstract

The invention provides an aircraft performance evaluation model construction and evaluation method based on arm angle influence, and the method comprises the steps: building a traditional flight mechanical model based on a power unit model, a control efficiency model, a rigid body dynamic model and a rigid body kinematic model, and obtaining various aerodynamic parameters of an aircraft arm at different angles through CFD simulation; the method comprises the following steps: constructing aerodynamic relation models at different angles, embedding the aerodynamic relation models into a traditional flight mechanical model to obtain a flight mechanical model based on arm angle influence, and constructing a flight performance simulation evaluation model based on a power unit model, a control efficiency model and the aerodynamic relation models. According to the method, more reliable aircraft scheme evaluation and higher-precision flight performance calculation are realized. The construction of a flight performance model fusing the influence of the external parameters of the aircraft also has expansibility, and the flight performance model can be embedded into an influence model of other appearance parameters and is used for evaluating the flight performance of multi-rotor aircrafts of different configurations.

Description

Technical Field

[0001] The present invention relates to the technical field of aerospace multi-rotor flight mechanics, and in particular to a method for constructing and evaluating an aircraft performance evaluation model based on the influence of an aircraft arm angle. Background Art

[0002] The traditional flight mechanics model includes four parts: power unit model, control efficiency model, rigid body dynamics model and rigid body kinematics model. Rigid body kinematics has nothing to do with mass and force, and only studies parameters such as position, velocity, attitude, angular velocity, and often uses a particle as a model; the rigid body dynamics model is roughly the same as the kinematics model, and the biggest difference is that the direction of the pulling force is always consistent with the negative direction of the Zb axis of the body. The two models are collectively called the flight control rigid body model, which is mainly used in the flight control system of the aircraft.

[0003] The power unit model and control efficiency model are mainly used to calculate various aerodynamic parameters and power parameters related to the aircraft itself, and are directly related to the performance of the aircraft. Conventional flight performance calculations also rely on these two models. The flight performance of an aircraft is not only related to the power unit, but also to the aerodynamic shape of the aircraft itself. Most of the existing flight performance calculation models ignore the impact of the aircraft's shape parameters on the results, or simplify the shape parameters. Therefore, constructing a flight performance calculation model that integrates the impact of aircraft shape parameters is of great significance for obtaining higher-precision aircraft performance and evaluating the overall aircraft plan. Summary of the invention

[0004] In order to solve the problems of the prior art, the present invention provides a method for constructing and evaluating an aircraft performance evaluation model based on the influence of arm angles, thereby achieving more reliable aircraft scheme evaluation and higher-precision flight performance calculation. The model can be embedded with influence models of other shape parameters to evaluate the flight performance of multi-rotor aircraft of different configurations.

[0005] The present invention provides a method for constructing an aircraft performance evaluation model based on the influence of an arm angle, and a traditional flight mechanics model is established based on a power unit model, a control efficiency model, a rigid body dynamics model, and a rigid body kinematics model, and specifically includes the following steps:

[0006] 1) Obtain various aerodynamic parameters of the aircraft arm at different angles through CFD simulation, and construct aerodynamic relationship models at different angles;

[0007] 2) The aerodynamic relationship model is embedded in the traditional flight mechanics model to obtain a flight mechanics model based on the influence of the arm angle, specifically:

[0008] 2.1) Based on the aerodynamic relationship model, new aerodynamic parameters are obtained according to the arm angle;

[0009] 2.2) Using the aerodynamic parameters obtained in step 2.1), the original aerodynamic parameters in the power unit model and the control efficiency model are replaced, and new dynamic parameters are obtained through the power unit model and the control efficiency model based on the parameters;

[0010] 2.3) Using the dynamic parameters obtained in step 2.2) to replace the original dynamic parameters of the rigid body dynamics model and the rigid body kinematics model, embedding the aerodynamic relationship model, and obtaining the flight mechanics model based on the influence of the arm angle;

[0011] 3) Construct a flight performance simulation evaluation model based on the power unit model, control efficiency model and aerodynamic relationship model;

[0012] The present invention also provides an aircraft performance evaluation method based on the influence of the arm angle, comprising:

[0013] 1) Import the PWM wave values ​​that control the multi-rotor aircraft into the simulation model and output the flight parameters of the aircraft, including rotor speed, torque, current and attitude;

[0014] 2) Input the external parameters of the aircraft (including aircraft weight, number of rotors, altitude, temperature, and rotor parameters) into the power unit model, and output the flight parameters of the aircraft after simulation by the inverse force model and torque model, including rotor speed, torque, force coefficient, and drag coefficient;

[0015] 3) The parameters obtained from the power unit model are input into the control efficiency model. After simulation by the motor model, the electric control model and the battery model, the current and voltage parameters required for calculating the flight performance of the aircraft are output;

[0016] 4) Inputting the simulated parameters obtained in step 2) and step 3) into the multi-rotor aircraft control rigid body model (including a rigid body dynamics model and a rigid body kinematics model), and obtaining the attitude parameters of the aircraft after simulation, including position, acceleration, and velocity;

[0017] 5) Calculate the impact of different arm angles on the aerodynamic parameters of the aircraft power unit components through CFD simulation;

[0018] 6) After summarizing the CFD data, the "Fitting" toolbox in Matlab is used to obtain the aerodynamic parameter change curves under different arm angles by curve fitting (quadratic fitting). The curve results are embedded in the power unit model and the control efficiency model. After simulation, the flight performance parameters of the aircraft at different flight speeds are obtained, including "maximum endurance time", "maximum level flight speed", "longest range", "long flight speed and long-distance flight speed";

[0019] 7) Evaluate the effect of the configuration scheme of the multi-rotor aircraft based on the flight performance parameters obtained in step 6).

[0020] The beneficial effects of the present invention are:

[0021] 1. The present invention constructs a flight performance calculation model that integrates the influence of aircraft shape parameters to achieve more reliable aircraft solution evaluation and higher-precision flight performance calculation.

[0022] 2. The construction of the flight performance model that integrates the influence of the external parameters of the aircraft is also scalable and can be embedded with the influence models of other appearance parameters to evaluate the flight performance of multi-rotor aircraft with different configurations. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0024] Figure 1 This is a diagram of a quadrotor flight performance simulation model based on the influence of the arm angle in an embodiment of the present invention;

[0025] Figure 2 This is a schematic diagram of a power unit model in an embodiment of the present invention;

[0026] Figure 3 This is a control efficiency model architecture diagram in an embodiment of the present invention;

[0027] Figure 4 This is a diagram of the rigid body dynamics model architecture in an embodiment of the present invention;

[0028] Figure 5 This is a diagram of the rigid body kinematics model architecture in an embodiment of the present invention;

[0029] Figure 6 : is a graph showing the relationship between the number of iterations and lift obtained by CFD simulation at different arm angles in an embodiment of the present invention;

[0030] Figure 7 : is a graph showing the relationship between the number of iterations and the lift coefficient obtained by CFD simulation at different arm angles in an embodiment of the present invention;

[0031] Figure 8 : is a relationship diagram between the number of iterations and the drag coefficient obtained by CFD simulation at different arm angles in an embodiment of the present invention;

[0032] Fig. 9are specific values ​​of various aerodynamic parameters obtained after CFD simulation convergence in the embodiment of the present invention;

[0033] Fig.10 This is a calculation result diagram of the flight performance simulation model in an embodiment of the present invention;

[0034] Fig.11 This is a diagram of isometric energy consumption results at different speeds calculated by the flight performance simulation department in an embodiment of the present invention. DETAILED DESCRIPTION

[0035] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0036] like Figure 1 As shown, a four-rotor flight performance simulation model based on the influence of the arm angle includes a power unit model 1, a control efficiency model 2, a control rigid body model 3 (including a rigid body dynamics model and a rigid body kinematics model) and an aerodynamic relationship model. A traditional flight mechanics model 4 is established based on the power unit model, the control efficiency model, the rigid body dynamics model and the rigid body kinematics model. The control of the multi-rotor aircraft is carried out through PWM waves, and the corresponding PWM wave values ​​are imported into the power unit model 1. The power unit model outputs various parameters such as the rotor speed, torque, current and attitude of the aircraft according to the PWM wave and external input parameters, and these output parameters are input into the control efficiency model 2 as input parameters. After simulation by the motor model, the electric adjustment model and the battery model, the current, voltage and other parameters required for the calculation of the aircraft flight performance are output. The influence effect of each aerodynamic parameter is determined by the aerodynamic relationship model 5, and the influence effect is coupled to the flight performance simulation evaluation model, and the various flight performances finally affected by the aerodynamic parameters are output.

[0037] like Figure 2 As shown, the external parameters of the aircraft (aircraft weight, number of rotors, altitude, temperature, rotor parameters, etc.) are input into the power unit model, and the aircraft's rotor speed, torque, thrust coefficient, drag coefficient and other parameters are output after simulation by the thrust inverse model and torque model.

[0038] like Figure 3 As shown, the parameters obtained from the power unit model are input into the control efficiency model. After simulation by the motor model, the electric control model and the battery model, the current, voltage and other parameters required for calculating the flight performance of the aircraft are output.

[0039] like Figure 4 and Figure 5 As shown, the parameters after simulation of the power unit model and the control efficiency model are input into the multi-rotor aircraft control rigid body model, and the attitude parameters such as the aircraft position, acceleration, and velocity are obtained after simulation.

[0040] like Figure 6-8 In order to calculate the impact of different arm angles on the aerodynamic parameters of the aircraft power unit components through CFD simulation, the three figures show the relationship between the number of iterations and lift, lift coefficient, and drag coefficient.

[0041] like Fig. 9 As shown, after the CFD simulation calculation converges, the average value of each aerodynamic parameter after convergence can be output in the software, and the value can be input as a parameter value into the flight performance simulation evaluation model to evaluate the flight performance after being affected by the aerodynamic parameters.

[0042] like Fig.10 As shown in the figure, after the CFD data are summarized, the aerodynamic parameter change curves at different arm angles can be obtained by curve fitting, and the curve results are embedded in the power unit model and the control efficiency model. After simulation, the flight performance parameters such as "flight power consumption", "maximum range", "long-term flight speed and long-distance flight speed" of the aircraft at different flight speeds (hovering speed is 0m / s) are obtained. The final parameters can be used to evaluate the effect of the configuration scheme of the multi-rotor aircraft.

[0043] like Fig.11 As shown in the figure, it is the result diagram of isometric energy consumption at different speeds calculated by the flight performance simulation department. Through this figure, the changing trend of the isometric energy consumption of the aircraft at different flight speeds can be obtained, which is used to evaluate the flight performance of the aircraft, where the isometric energy consumption is expressed as: the energy required for the aircraft to fly 1 meter, in J (joule).

[0044] As shown in Table 1, after selecting aircraft performance data of 5 types of aircraft (a total of 7 different models) on the market, including existing aircraft products and scientific research aircraft, the present invention uses a traditional flight performance calculation model and a flight performance simulation model based on the influence of the arm angle constructed by the present invention to simulate and calculate, and obtain the flight performance data calculated by different models. By comparison, it is found that the average accuracy of the model constructed by the present invention can be improved by 19% compared with the traditional model.

[0045] Table 1

[0046]

[0047] Each embodiment in this specification is described in a progressive manner, and the same or similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the device embodiment, the above is only a preferred embodiment of the present invention. Since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment. The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited to this. Any technician familiar with the technical field is within the technical scope disclosed by the present invention. For ordinary technicians in the technical field, changes or replacements that can be easily thought of should be covered within the protection scope of the present invention without departing from the principle of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A method for constructing an aircraft performance evaluation model based on the influence of the arm angle, which establishes a traditional flight mechanics model based on a power unit model, a control efficiency model, a rigid body dynamics model, and a rigid body kinematics model, characterized in that The specific steps include: 1) Obtain various aerodynamic parameters of the aircraft arm at different angles through CFD simulation, and build aerodynamic relationship models at different angles; 2) The aerodynamic relationship model is embedded in the traditional flight mechanics model to obtain a flight mechanics model based on the influence of the arm angle, specifically: 2.1) Based on the aerodynamic relationship model, new aerodynamic parameters are obtained according to the arm angle; 2.2) Using the aerodynamic parameters obtained in step 2.1), the original aerodynamic parameters in the power unit model and the control efficiency model are replaced, and new dynamic parameters are obtained through the power unit model and the control efficiency model based on the parameters; 2.3) Using the dynamic parameters obtained in step 2.2) to replace the original dynamic parameters of the rigid body dynamics model and the rigid body kinematics model, embedding the aerodynamic relationship model is achieved, and obtaining the flight dynamics model based on the influence of the arm angle; 3) Construct a flight performance simulation evaluation model based on the power unit model, control efficiency model and aerodynamic relationship model.

2. A method for evaluating aircraft performance based on the influence of aircraft arm angle, characterized in that: 1) Import the PWM wave values ​​controlling the multi-rotor aircraft into the flight performance simulation evaluation model, and output the flight parameters of the aircraft, including rotor speed, torque, current and attitude; 2) Input the external parameters of the aircraft into the power unit model, and output the flight parameters of the aircraft after simulation by the inverse force model and torque model, including rotor speed, torque, force coefficient, and drag coefficient; 3) The parameters obtained from the power unit model are input into the control efficiency model. After simulation of the motor model, the electric control model and the battery model, the current and voltage parameters required for calculating the flight performance of the aircraft are output; 4) Input the simulated parameters obtained in step 1), step 2) and step 3) into the multi-rotor aircraft control rigid body model, and obtain the attitude parameters of the aircraft after simulation, including position, acceleration and velocity; 5) Calculate the impact of different arm angles on the aerodynamic parameters of the aircraft power unit components through CFD simulation; 6) After summarizing the CFD data, the aerodynamic parameter change curves at different arm angles are obtained by curve fitting. The curve results are embedded in the power unit model and the control efficiency model. After simulation, the flight performance parameters of the aircraft at different flight speeds are obtained, including "maximum endurance time", "maximum level flight speed", "longest range", "long flight speed and long-distance flight speed"; 7) Evaluate the effect of the configuration scheme of the multi-rotor aircraft based on the flight performance parameters obtained in step 6).

3. According to claim 1, it is characterized in that: Step 2) The external parameters of the aircraft include aircraft weight, number of rotors, altitude, temperature, and rotor parameters.

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